During the course of a surgical operation on a patient, it is often necessary to remove from the site of the operation various body fluids, including blood, which tend to collect there. During childbirth, it is often necessary to remove meconium from the newborn using an intrapartum nasopharyngel suction device. In either case, the suction probe or catheter is usually connected to a pump or other type of vacuum source by means of a flexible tube. It has been found convenient to install a relief valve between the suction probe and the pump in order to control the amount of vacuum applied to the probe. Such a suction control usually consists of a valve which can be adjusted to admit a certain flow of ambient air into the tube, thus, reducing the suction force at the probe.
In some suction devices, the air intake of the regulating valve is controlled by the operators positioning a finger over the air-intake as disclosed in U.S. Pat. No. 5,000,175, Pue. Such a device must be continuously handled by the operator. Moreover, should the operator drop the device, the maximum rate of ambient air is admitted, thus reducing or completely interrupting the suction.
Other medical suction control devices, such as the one disclosed in U.S. Pat. No. 4,356,823, Jackson, offer only a limited range of vacuum adjustments and no way to adjustably stabilize the setting of the air-intake.
Similar suction control devices in the prior art have been difficult or inconvenient to operate while being gripped with one hand. Also, they may be subject to inadvertent adjustment when tension is applied to the suction tubing.